They are an unequal group in economic volumes, with China leading the way and South Africa being the smallest economically.

O'Neill had always had misgivings about South Africa being in the group, but thinks it should be there, despite its economy being the smallest at about 300 billion dollars a year.

"China creates another South Africa (economically) every six months, how on earth can South Africa be economically in the same class?" the economist said.

"Politically, it is very important that South Africa is part of BRICS," said O'Neill, who was a minister in the British government until late 2016.

His responsibility was to craft a response to the danger of Anti-Microbial Resistance (AMR), an issue he took to the G20 Summit last year in China's Hangzhou.

It was there he saw the benefit of South Africa.

"I have seen, because of my role in health, South Africa take a lead. Last year's G20 Summit in Hangzhou included a statement about AMR -- it would not have happened if it had not been for South Africa supporting its inclusion," said O'Neill.